Communications Propagation Trials During the British North Greenland Expedition October 1952 to July 1954

This paper summarizes an analysis of observational data recorded during the above expedition. Several stations mainly in the United Kingdom, transmitting on low, medium and high frequencies were monitored for signal strength, readability and interference, using the SINPO code, at two sites. Main base at latitude 77°09'N longitude 23°57'W and Northice latitude 78°04'N longitude 38°29'W. The assessment of circuit performance made on such data is necessarily qualitative. The analysis shows that 24-hr high frequency communications is possible during normal ionospheric conditions if the terminals are chosen so that the reflection points avoid the auroral zone. Frequency predictions were found generally to be slightly low but gave a useful guide to the working frequency. In disturbed conditions high frequency circuits were interrupted, even for small disturbances, and blackouts occurred at times. However, on circuits less than 900 miles long where the reflection point was outside the auroral zone, there was no apparent limit on performance. No evidence of sporadic-E propagation was found. Medium frequency communications were consistently good at night and practically useless by day, irrespective of ionospheric conditions. Low frequency communication was possible by day and night and was most stable for frequencies below 100 kc/s. During an h. J. blackout, low frequency signals were strong but in partially disturbed conditions reception was more variable. Whilst no noise measurements were made reports showed that the noise level was very low in normal conditions, and that it increased in disturbed conditions, being particularly high at low frequencies.